Valve



Mardi 1s, 1941. C.' E TOUSSAINT 2,235,304

VALVE Filed Dec. l, 1938 C HJM@ Patenteaomar. 1s, 1941 VALVE Charles F.Toussaint, Chicago, lll., assigiior to Perfection Gear Company, Harvey,Ill., a corporation of Illinois Application December 1, 193s, smal No.243,321

4Claims.

This invention relates to valves for governing the flow of uids and moreparticularly to a main valve and a pilot; controlling valve togetherwith damping means for insuring stability in the joint 5 and severaloperations of Ithe valves, For governing the now of uids such as gas orliquid, in large quantities or under high pressures or both, it isnecessary to have substantial power for operating the valve. 'I'hesetting of such valves is frequentvalve is controlled by a smaller pilotvalve. This' pilot valve is small enough to be susceptible to directcontrol by the supervising means or manual means as desired. Physicallythe two valves are distinct so that the physical operation of one valvedoes net directly aifect the other valve except by means of viiuidpressure changes transmitted from one to the other. While in the -valveshown, both pilot and main valves are combined into a compact structure,there is no reason why the two valves cannot be physically distinct fromeach other and connected by 'suitable conduits.

Because the two valves are physically independent of each other, it ispossible to use a l standard valve as -the pilot. 'Ihus for differentsizes of main valves, the same pilot valve may be used. This isimportant from a cost viewpoint since pilot controlled valves are rarelymade in one size in large quantities. By thus standard- 40-izing on asubstantial part of the entire pilot controlled valve, considerablesaving is possible on diierent sizes of valves.

The pilot valve 1s provided with damping means to prevent too suddenchanges or'oscillations in the valve setting. In order to promote smoothpilot valve operation and prolong the useful lifeV thereof, the dampingmeans is sealed against the ingress of dirt -or contaminating fluids.Hence a valve of this character may be used for the conv trol' ofcorrosive uids or-'iluids whose purity must be maintained at a highvalue and not contaminated by the damping nuid, if diierent from thefluid controlled.

Additional damping means is provided in the interconnecting conduits toprevent Vundesirable reaction of one valve on the other. 'I'hisadditional damping is operative independentlyv of the pilot-valvedamping and may be used alone if desired.

Because the pilot and main valves are separate, there is also a minimumof machining operations. In fact the Aonly precision ports of the mainvalve are the valve member and seat. Otherwise few finishing operationsare necessary.

Means are also provided for screening the iluid going through the pilotvalve so that little if any dirt is lilzely to get on the pilot valveseat or clog the connecting conduits. f

In general, the invention contemplates a main valve having a valvemember on the high' pressure side'of the main valve seat. Forming oneboundary or wall of the main high pressure region is a exible memberwhich is adapted to move'in response to the difference in pressure onopposite sidesA thereof. The main valve vmember is subjected to aresultant force which is the ible member and a constant force tendingltoclose the valve. A pilot -valve is provided and has its high pressureregion connected by a restricted conduit with the main inlet or highpressure region. The pilot high pressure region is also connected by aconduit` which may be restricted toa chamber formed in part by theilexible member, which thus functions as a partition between the chamberand mainhigh pressure region. The pilot low pressureregion is connectedby a conduit to the main outlet or 'low pressure region. The pilot valveitself has a valve member which Vmay be either in the pilot low or highpressure regions, although shown inthe high pressure region.

Thus at the pilot valve, the iluicl pressure is directed along twopaths. One path leads from the high pressure pilot side to the chamber'.and sets up a static pressure on the flexible member in opposition tothe main high pressure. The other-path at the pilot valve, when thevalve is open, is a low fluid resistance path to the iluid discharge ofboth valves.

composite of the force tending to move said liex- 'Normally the staticpressure may. more than y balance the high pressure'on the exiblemember,

due to the difference in effective area, with the result that ,the mainvalve member is closed. However, when'the Ypilot valve opens, thepressure in the pilot high pressure region is reduced because of thepressure drop in the supply conduit. This results in a pressure drop inthe chamber. Hence a suillcient pressure diilerential between the mainhigh pressure region and chamber vmay exist to force the flexible memberto open the valve. By providing a restricted conduit between the pilothigh side and chamber a dampingl action is created. However additionalclamping Vmeans on the pilot valve member is preferred.

Referring to the drawing. the single figure is a sectional-view of thepilot controlled valve, with arrows showing the path of main and pilotuid. v

As pointed out above, the main and pilot valves are physically separatealthough their casings have been combined somewhat. n The main valve isprovided with a main casing Il of suitable material such as iron. Thiscasing has an inlet port II and an outlet port I2. Inlet port I| opensintoa main high pressure' side or region I3 while outlet port I2 opensinto a low pressure side or regio'l. I4. A partition I5 having anaperture I6 separates these two regions. Partition I5 has suitablydisposed therein, as by a press fit, a valve seat |1 of any suitablemetal. Itis understood of course that this valve seat is accuratelyfinished at the seat proper;

Disposed in the main high pressure region I3 is a valve member generallydesignated as 20. This member comprises a body 2| having an annularinsert 22 which actually functions as the valve member proper incooperationwith valve seat I1. This insert 22v is made of suitable metaland finished off so that a fluid tight seal at the main valve surfacesis obtained. Valve member body 20 has a bolt-like projection 23 uponwhich is threaded a guide 25. This guide has a plurality of fingers 26which work inside aperture I6 against the opposing face of the seatinsert I1. The guide 25 maintains the annular valve insert 22 inposition and also maintains the valve in a true position duringoperation.

In line with bolt portion 23 is a second bolt portion 28 projecting fromthe valve member body 20. Disposed aroundbolt portion 28 are two metalwashers 30 and II having their edges curled away from each other asshown. Between these washers is a flexible member or diaphragm 33 ofrubber, leather, copper or any other suitable material which extends tothe casing proper and which forms a wall for the main highpressureregion I3. A nut I5 on bolt portion 20 is provided for rigidly clampingthe flexible member between the washers 30 and 3|.

casing 4II has an'inlet port 4I and an outlet port 42 separated by apartition 43 suitably apertured at 44 and provided with a valve seat 45.This seat may be of suitable material and as shown here is threaded intoplace. The active side of the seat facesl a' pilot high pressure region45.

Pilot inlet 4I is connected by a conduit to main inlet II. This conduitcomprises a restricted 'channel 41 formed in a metal insert 4I.v Thisinsert. has a tubular projectionv Il extending into 'a large channel 5|formed in the main valve casing Il and leading from a portion ,of themain valve inlet. Insert 4l has a pipe 53 set into the and main inlet'II', the only element of importance' is bore 41. The insert is merely amatter of convenience so that different size bores may be used tocontrol the valve characteristics.

Pilot outlet 42 is connected by a conduit 5I to main valve outlet I2.This'conduit is preferably large enough to permitv the free iiow ofAfluid passed by the pilot valve.

Threaded into an interior portion of pilot 20 valve casing 45 is apilotvalve member assembly generally designated as 5 2. This assemblycomprises a body 53 having a cylinder 84' facing the pilot valve seatand having a head 65 projecting into a chamber 56. 'This chamber V|56 isformed by pilot casing 40 together with head 65 and flexible member 33.Around head 65 is a coil spring 58, one end of which rests against ashoulder 68' of the pilot valve'member assembly and the other end ofwhich is disposed on washer 3|. Springv 8l tends to press the main valvemember down into closed position. Preferably head 65 is near enough tothe main valve member to limit its opening movements to a point whereguides 25 are stili operative.

Body 63 of the pilot valve member assembly is provided with a channel10, part'of which is constricted at 1|, to form a restricted conduitbetween the pilot valve high pressure region 45 and chamber 66.

Slidably disposed in cylinder 64 of the pilot valve member body is apiston 13f having an enlarged head 14 into which is disposed an annularvalve member insert 15. This insert is made of suitable material,finished accurately so'that with its seat 45 a fluid tight pilot valveresults. Surrounding piston I3 is a cylindricalcorrugated bellows 11 ofsuitable material such as copper'. The ends of bellows I1 are sealed topiston head 14 and a shoulder 1l on body 63. The interior of piston 13is vhollowed out as shown. A coil spring, is disposed in cylinder 64between the opposing piston and body faces to bias the pilot through thepilot valve casing 40 into aperture 44 is adapted to bear-againstsealing -screw II to control the position of the pilot valve. Itis understood of course that other sealing means may be used, such assolder. In fact, if a hermetic seal is necessary, screw 8| may besoldered in place.

cynmierV u of the punt vave 1s fined-with any suitable medium fordamping purposes. Thus oil,

glycerine or any liquid may be used in combina.

tion wi-tha suitable air space. Air or gas alone may be used if desired.

It is understood of course that piston 13 has sufficient clearance to'permit leakage of the damping medium into the space Just inside ofbellows 11.

The operation of the valve while described in general terms previouslymay be briefly reviewed.

' Normally with the pilot valve closed, static inlet of the ilexiblemember 33 will have no effect in the absence of iiuid ow therethrough.Upon ,the opening of the pilot'valve, a sustained pilot iluid flow willbe established right through the pilot valve aperture 44. This sustainedflow through constricted bore 41 will cause the pressure in region 46,the pilot high pressure region, to be less than the pressure in maininlet Il or main high pressure region I3. The reduced pilot highpressure will be communicated to chamber 66 and thus result in apressure differential on flexible member 33. The resulting movement offlexible member 33 will cause main valve member 2li to be pulled awayfrom its seat and establish a fluid iiow through the main valve.

It should benoted that the bore 41 in the conduit between the two highpressure regions is solely responsible for main valve opening movements.The constriction 1| in the conduit between the pilot high pressureregion and chamber 36 merely prevents sudden pressure changes in chamber66. The rluid flow through this latter conduit is not sustained but ismerely a displacement Aflow to compensate for volumetric changes inchamber 66 due to the movement of flexible member 33 and thus tends todamp the movement of the main valve.

The additional damping action of thepiston 13 in cylinder 64 isobvious.- This damping is applied to pilot valve member and stabilizesthe valve. Y

It is desirableto concentrate the pilot iiuid pressure drop in bore 41so that accurate control of the valve characteristics will result frombore control.

It will be clear that oscillation or hammering will be impossible withthe construction shown. This is important when handling incompressiblefluids as water. Thus the cylinder 64 and piston 13 damp the operatingrod 83 and pilot-valve member proper. Restriction 1I damps any surgesbetween chamber 66 and the pilot high pressure region. In other wordssudden reaction between tthe pilot valve and main valve through chamber66 is eliminated. .Constrlction 41 also prevents,

sudden reaction between the two valves because of any possible pressuresurges ln the main high pressure region. The heavy damping preventsoscillations from being generated but permits the valves -to cooperate.

It is obvious that the pilot valve and main valve may be remote fromeach other.- Thus the two restricted conduits can be as long as desiredwithin obvious limits.' While the pilot valve member head 65 functionsasan anchor for the main valve spring and also vas a stop to limit theopening movement of the main valve member, it is obvious that these twofunctions could be performed by the main valve casing if necessary.

It is also understood that the pilot valve mem` ber need not necessarilybe on the high side. The valve proper and seat may easily be disposed inthe low pressure region 42.

One. important element in the design of the valve system is the ratio ofarea of flexible member to that of the main valve member facing apertureI6. With the main valve member closed, a substantial area facingaperture I6, is not under high pressure. I'his means that there is apres sure differential on the valve proper which tends to keep itclosed, apart from the action of spring 68. This is the same as if therewas a difference in area between the two sides of the ilexible memberwith the larger effective area on the chamberv side. This difference inarea is 4the area of the main valve member facing aperture I6.

Obviously the greater the ratio of flexible meml ber `area to the valvearea facing aperture I6, the smaller will be the differential force onthe exible member, assuming equal pressures on opposite sides, incomparison to the total force acting on a side of the iiexible member.

Thus it is possible to have the flexible member area small enough incomparison to the valve area to cause the main valve to have only twostable positions; i. e. closed or full open. After the main valve memberhas opened somewhat, the additional area facing aperture I6 .is

. made available as an operating force so that an additional opening`force is generated. In such case, a trigger action will result with thepilot valve merely closing or fully opening the main` valve. For certainpurposes this action is highly desirable. Thus if water havingsubstantial sediment is being handled, the sudden full opening of themain valve is desirable to flush the valveclean.

On the other hand, if the valve area is small in comparison to theexible member area, then the differential force may become so small thatit loses its critical power. In that case a modulating action can beobtained with the main valve following the pilot valve in apredetermined fashion. Hence by controlling the fluid resistancecharacteristics of the bore 41 and controlling the ilexible member.areav as compared to the main valve area, radically different valvecharacteristics may beobtained. It is clear that as .the main valvebecomes more of a two position l valve, the necessity for a spring biasdisappears. When the main valve member is closed or even just barelyopen, a strong closing force isgenerated on the valve itself.v

Another factor which has some eiects 4onv valve operation is the fluidflow resistance through the main valve. This may be very low if desired.There will always bea pressure differential on opposite sides of thevalve apertures, both main and pilot, and in view .of-that the termshigh pressure and low pressure have been used. It is to be understood,however, that these terms merely describe the side of the valveaperturetobe considered and do not necessarily imply any substantial pressuredifferential.

The valve proper may have rubber valveme ber inserts. 1n this way, thenecessity for accurate machine work is eliminated; In'the case where themain valve merely opens or closes all the way, the rubber insert isparticular-ly desirable. The valve can be designedso that it closesrmlyand quickly. With` metal to metal action, a quick hard closing wouldtend to wear the valve and make considerable noise.

What I claim is:

1. In combination, a main valve and'pilot controlling valve therefor,comprising individual -valve casings, each casing having an aperturedpartition separating each casing interior into Vhigh and low pressureregions, mainand pilot valve members cooperating respectively withthemain and pilot apertured partitions to control theA yfiowvof iiuidtherethrough, said main valve member being on the high pressure side ofthe cooperating partition, mean-s for biasing.l said main valve memberto a closed position, means external to the valves for controlling thepilot .valve member, a sealed chamber adjacent the main high pressureregion and having as a partition therebetween a pressure responsiveflexible member1 means connecting a movable portion of said ilexiblemember to said main valve member to impart valve controlling movementsthereto with saidmain valve tendng to open upon main high pressureregion enlarging movements of said ilexible member, a iluid conduitconnecting! the two low pressure regions, a second uid conduitconnecting the pilot high pressure region and said chamber, and a thirdfluid-conduit connecting the two high pressure regions, said secondconduit being restricted in comparison to the volume of said sealedchamber to resist sudden volumetric changes in said sealed chamber andsaid third conduit being restricted in comparison to both said rstconduit and the iluid path through said main valve when op'en whereby ailuid pressure drop in said third conduitl occurs on fluid ilowtherethrough, said pressure lses , erating partition, means for biasingsaid main valve member to a' closed position, means external to thevalves for controlling the pilot valve member, means for maintainingsaid two casings togetherto Vform a sealed chamber adjacent the mainhigh pressure region and having as a partition therebetween a pressureresponsive iiexible member rigidly clamped at its edges between the twocasings and carrying the main valve member at the center thereof, saidflexible member serving to impart valve controlling movements theretowith said main valve tending to open Vupon main high pressure regionenlarging movements of said ilexible member, a uid conduit connectingthe two low pressure regions, a second fluid conduit connecting thepilot high pressure region and said chamber, and a third tluid conduitconnecting the two high pressure regions, said second conduit beingrestricted in comparison to the volume of said sealed chamber to resistsudden volumetric changes in said sealed chamber and said third conduitbeing restricted in comparison to both said ilrst conduit and the fluidpath through said main valve when open whereby a lluid pressure drop in`said third conduit occurs oniiuid ilow therethrough, said pressure dropbeing communicated to said sealed chamber interior to thus create apressure diiIerential on oDpOsite sides of said ilexiblemember for mainvalve opening movement.

3. In combination, a main valve and pilot controlling valve thereiorcomprising individual valve casings, each casing having an aperturedpartition separating each casing interior into high and low pressureregions, main and pilot valve members cooperating respectively with themain and pilot aperturedY partitions to control the ilow of iluidtherethrough, saidmain valve member' being on the high pressure side ofthe cooperating partition, means for 1biasing said main valve member toa closed position, means external to the valves for controlling thepilot valve member, means for maintaining said two casings together toform a sealed chamber therebetween adjacent the main high pressureregion and having as a partition therebetween a pressure responsiveilexible member, means tot mounting said main valve member at av movableportion of said ilexible member to impart valve controlling movementsthereto, with said main valve tending to open upon main high pressureregion enlarging movements of said ilexible member, a guide on said mainvalve member cooperating with the mainipartition to maintain said mainvalve member in aligned position, means carried by said pilot valvecasing to limit the opening movement of said main valve member, a iluidconduit connecting lthe two low pressure regions, a second iluid conduitconnecting-'the pilot high pressure region and said chamber, and a thirdiluid conduit connecting the two high pressure regions, said thirdconduit having a fluid ilow resistance high in comparison to that of anypath having a sustained iluid ilow.

4.*The combination of claim 3 wherein said pilot valve member and themeans for limiting the movement oi' said main valve member form a partof an assembly uni-t in said pilot valve casing.

cHARms F. 'r'oUssAImx 50 mounted as a removable

